The concept of using blocks, or other elements for retaining soil, or other landscaping applications, is known. U.S. Pat. No. 5,119,587, issued to Waltz, provides for irregularly shaped landscaping blocks which have holes provided through extending portions, so that an additional element may be extended through the blocks, holding them in place. U.S. Pat. No. 1,634,357, issued to Himmelright, discloses a refractory block wherein one block has a pair of nubs, or protrusions on one side, and a corresponding set of indentations on the other side of the block. A similar concept is disclosed in U.S. Pat. No. 5,230,195, issued to Sease, which likewise discloses a pair of protrusions on one side of the block with a pair of corresponding indentations on the opposing side. U.S. Pat. No. 5,505,034, issued to Dueck, also discloses a retaining block utilizing extensions, or nubs, as a connecting feature. Documentation of Adam Sehring & Sohne, a German manufacturer, discloses a retaining wall block element which requires the use of a fastening device which is not inherent within the retaining wall block element itself.
There are many products which are utilized as landscaping blocks. None, however, incorporate the particular features of the instant invention. The Waltz patent, and similar applications, also lack the ability to make angles of 90.degree. or greater and demand the use of additional pieces or pins to provide interlock, or the use of a "cap block" to give the project a finished look, as, often, unless two different types of blocks are used, the upper level of the block, without the "cap block," would show the perforations or indentation used to interlock the blocks. Other known uses include smaller retaining wall blocks which comprise a one-piece system, but do not have the ability to interlock with each other and have to be cut to produce corners. There is no previously known system utilizing a singular unit only, which provides interlock, allows up to 180.degree. exterior angles in a landscaping project perimeter and which may be easily produced on a conventional block or paver-producing machine. In addition to blocks, timbers and treated 2.times.4's, among other materials, have been utilized as landscaping blocks for edges and surrounds, as well as for flower planters and the like. Such wood products have to be cut in length and fastened mechanically. They are subject to decay and deterioration as well. Conventional clay bricks and concrete blocks have also been used, but provide no interlockings or horizontal or vertical fastenings, which allows for movement between the elements. Small retaining wall blocks may solve the vertical interlock problem, but do not address the horizontal interlock. Small retaining wall blocks also require cutting to make corners and many need pins to interlock and a cap to finish the top to provide the appearance of a smooth unitary surface. Others may require multiple pieces for interlock. Poured-in-place concrete has also been used, but requires more excavating, needs finishing after placement, is prone to cracking, and cannot be transported in units.
The ideal solution for a landscape block would require only one piece, provide interlock both horizontally and vertically, be able to be installed making angles up to 180.degree., be useful for planters, edges, surrounds and steps, be able to be produced with minimal labor on a conventional block machine, be easily made and packaged, be easy to install and long-lasting, all the while requiring very little modifications to complete a project. While a number of products currently being used as landscaping blocks may fill one or more of these requirements, none, save the present invention, fulfills all of them. The Waltz patent and other similar applications require multiple pieces and do not allow for corners of 90.degree. or more and are difficult if not impossible to fabricate on conventional block machines. The invention disclosed by Dueck, and other similar inventions, requires modification to make square corners and angles of 45.degree. or more, and most require cap blocks to finish the product. Conventional bricks and blocks, as stated, do not provide any type of interlock, allowing for excessive movement. Accordingly, it is desirable to provide a landscaping block which is comprised of a singular unitary piece, can provide interlock both vertically and horizontally, which can be made on the conventional block machine, which can be utilized to form landscaping structures including angles of up to 180.degree., which may provide positive interlock and which interlock may permit rotation from the point of interlock or may not.